Introduction: Splenectomy is an important and potentially curative treatment for immune thrombocytopenia (ITP). Laparoscopic splenectomy (LS) has replaced open splenectomy (OS) as the standard approach. The prognostic role of platelet count and the clinical indication of preoperative platelet transfusion are not entirely clear. Methods: We designed a study to explore the prognostic impact of surgical methods, platelet count, and platelet transfusion in a large, single-institute, long-term cohort of ITP patients. Result: In 118 ITP patients, there was no difference between OS and LS in response and surgical complications. The overall response rate was 77% and the complete response (CR) rate was 70%. Patients with a CR had a trend towards a higher baseline platelet count. A stable platelet count 14–28 days after splenectomy was associated with a sustained long-term response. Patients requiring preoperative platelet transfusion had a lower preoperative platelet count and were more likely to need postoperative transfusion of red blood cells and platelets. They also had a lower postoperative platelet count than the nontransfusion group. Relapse-free survival did not differ. Conclusions: Baseline and postoperative platelet counts are apparently associated with the treatment response to splenectomy but the difference did not reach statistical significance. Preoperative platelet transfusion did not overcome the disadvantage of thrombocytopenia and was not recommended when other preparative measures are available.